The correct option is A Rainwater harvesting
Rainwater harvesting is the accumulation and storage of rainwater for reuse on-site, rather than allowing it to run off. Rainwater can be collected from rivers or roofs, and in many places, the water collected is redirected to a deep pit, a reservoir with percolation. Its uses include water for gardens, livestock, irrigation, domestic use with proper treatment, indoor heating for houses, groundwater harvesting.